Proportional preset dimmer scheme



June 7,1932. R WENSLEY 1,862,487

PROPORTIONAL PRESET DIMMER SCHEME Filed Nov. 15, 1929 h l 32-2; ial 2:32r I- 22 as 5 A.C.$up,oly '3 INVENTOR Roy J Wens/ey.

, ATTORNEY Patented June 7, 1932 PATENT OFFICE V UNITED STATES 'noY J.wE s EY, or" 'rrrrsnnncn, PENNSYLVANIA, ASSIGNOR 'ro ,wE'srINGHoUsEELECTRIC a MANUFACTURING COMPANY, A CORPORATION or PENNSYLVANIA IPROPORTIONAL PRESET DIMMER SCHEME Application filed November 13, 1929.Serial No. 408,968.

My invention relates to current-control apparatus and particularly toapparatus for controlling the intensity of the illumination in lightingcircuits used in theatres and auditoriums and for indoor and outdoorornamental lighting.

An object of my invention is to provide a current-controlling apparatuswherein the lighting circuits are controlled'by means-of is providedvfor controlling the supply of direct current to the control windings ofthe reactors and wherein the degree of illuminating intensity of lampsin the circuit is deter mined by the resistance element which may bepreset to ,produce predetermined lighting effects at any time as, forinstance, during v a scene of a theatrical production.

A further object of my invention is to provide a current-controllingapparatus for lighting circuits wherein a resistance element of simpleform is provided with a plurality of resistance sections that may beindividually preset to determine the degree of illumination of thelighting circuit.

A further object of myinvention is to provide a resistance device forcontrolling the control winding of a reactor in which all of the currentpassing through the resistance ele- 80 ment flows through the controlwinding of the reactor.

Further. objects of my" invention will be made apparentthroughout thefurther description of m invention and are obtained by the means theapparatus hereinafter described, and illustrated in the accompanyingdrawing, wherein,

The single figure diagrammatically illus trates the apparatus and wireconnections employed in the circuit-controlling apparatus or system.

The structure illustrated in the drawing represents the apparatusnecessary for a single lighting circuit, and it will be understood thatall lighting circuits required for the stage or auditorium of a'theatreorfor ornamental mobile lighting, paratus.

Referring to the drawing, the apparatus includes a uni-directionalcurrent source 2 reactors and wherein a resistance element containsimilar aphaving feed conductors 3 and 4 and an alternating-currentsource 5 having feed conductors 6 and 7. Each lamp circuit 8, comprisingconductors 9 and 11, is provided with a plurality of incandescent lamps12, and the current, supplied thereto from the alternating-currentsource, is controlled by means of a reactor 13 having an iron core 14that is provided with three legs 15, 16 and 17 The primary windings 18of the reactor are wound about the legs and 16 of the core and areconnected, at one end, to the feed conductor 6 and, at the other end, tothe lighting-circuit conductor 9, as indicated in the drawing.

. The control winding 19 for the reactor,

which is wound about the center leg 17, is supplied,with uni-directionalcurrent from a rectifier 21, the winding being connected to theterminals 22 and 23 thereof throughconductors 24 and 25, respectively.It will be understood that the control winding serves to' saturate thecore of the reactor and thus reduce the impedance of the primarywindings 18 substantially in proportion to the amount of direct oruni-directional current flowing through such control winding In orderthat the reactor 13 may be controlled by means of a minimum amount ofuni-directional current, I provide a relatively small reactor 26' thatis similar, in construction, to the reactor 13, its function being tosupply the control winding 19 of the reactor 13 with current fromitsprimary windings through a rectifier 21.

The reactor 26 comprises an iron core 27 having three legs 28, 29 and 31and primary windings 32 that surround the legs 28 and 29 and areconnected to the feed conductor 6 and a terminal 33 of the rectifier 21,the opposite terminal 34 of the rectifier being connected to the feedconductor 7.

Since the current required for the control winding of the reactor 13, isa very small portion of that required for the lighting circuit, Verylittle of the current output is required from the reactor 26 in order toprovide have, therefore, provided a relatively small resistance elementor unit 37 for controlling the current supplied from the unidirectionalsource to the control winding 35 of the reactor 26. The resistanceelement or unit 37 comprises a resistance member 38 that may consist ofa coil of resistance wire, such as nichrome, in the form of a closedring, as indicated in the drawing. A plurality of resister sections 41,42,43, 44, 45, 46, 47, as, 49 and 50, one for each scene of a stageproduction, for example, are connected to the resistance member I 38 atuniformly spaced points 51, and the outer ends of the resistancesections are connected, at uniformly spaced points, to a conductor 52that commonly connects all of the resistor sections and is connected tothe feed conductor 3 of the uni-directional source 2.

Each of the resistor sections 41 to 50, inclusive, is provided with anadjustable contact 53 on the free ends of a flexible conductor 54 whichserves to shut more or less of such resistor section.

The resistance of the resistance member 38. between two adjacent points51, is considerably greater than the resistance of any single resistorsection, 41 to 50, inclusive, in order that the current passing throughany section from the conductor 52 to the resistance member 38 shall belocalized to points within the immediate vicinity of the point ofconnection of a section to the resistance element 38. I

The resistance unit is provided with a master contact 55 that is carriedby a conductive operating arm 56 that is pivotally mounted to permitengagement 0 the contact 55 with the resistance element 38, at pointsthroughout its circumference, provided the arm is rotated through 360degrees. The contact 55 is connected to the control winding 35' of thereactor 26 through operating arm 56 and a conductor 57, it beingunderstood that the other end of the control winding is connected to thefeed conductor 4 of the unidirectional source 2.

For the purpose of illustration, it will be understood that the resistorsection 41 is adapted to control the lighting circuit 8 during theperiod ofscenel of a stage production, and resistor section 42 is forcontrolling the illumination of the same circuit-during the period ofscene 2, and so on. The degree of illumination for each scene will,therefore, be determined by theposition of the movable or adjustablecontact 53 with respect to its resistor section.

The reactors kind the resistance sections are so proportioned that, whena contact 53 is disposed midway of its resistor section when the mastercontact 55 isin engagement with the point of connection 51, the reactor13 will be so affected as to produce substantially 50% illumination.

, means? A movement of the contact 55 away from a point 51 will addresistance in the circuit through the control winding 35 and furtherreduce the illumination, if so desired, during any part of the scene,minimum illumination being produced for a particular preset position ofa contact 53 when the contact 55 is in the position midway between thepoint of connection 51 and its nearest neighboring point 51.

The operation of the device is as follows: uni-directional, or direct,current is supplied to the conductors 3 and 4 and, when the parts are inthe positions shown in the drawing, the current will flow from theconductor 3 through the flexible conductor 54, adjustable contact 53 andsubstantially one-half of the resistor section 41, then, throughsubstantially one-half of the portion of the resistance member 38, thatis, between two connection points 51, the contact 55, the operating arm56, conductor 57 and the coil 35, to th feed conductor 4.

By reason of the interposed resistance, very little current flowsthrough the control winding 35 and, consequently, the impedance of thecore 27 permits only a small quantity of current to flow from the feedconductor 6, through the primary windings 32 of the reactor 26, to theterminal 33 of the rectifier.

The rectified current supplied from the rectifier 21 to the conductor 25passes through the control winding 19 of the reactor 13 andcorrespondingly reduces the impedance of the reactor to such degree thatsufiicient current is permitted to flow through the primary windings 18to cause partial illumination of the incandescent lamps 12. To produce agreater amount of illumination, the operating arm 56 is moved toward theresistor section 41 until it engages the connection point 51, at whichtime the degree of illumination will be substantially 50%.- If it isdesired to increase the illumination to 100%, the contact 53 is movedinto engagement with the connection point 51, thereby shunting theresistor section 41 and permitting current to flow directly, and withoutresistance, from the feed conductor 3 to the contact 51 and thecontact55.

It will be apparent .from the foregoing that any number of scenes,within the capacity of the, apparatus, may be preset by presetting theadjustable contacts 53 to produce any desired illumination for aparticular scene. For instance, the illuminating effect for scene 5 isproduced by moving the contact 55 along the resistance member 38 untilit engages the connection point 51 of resistor section 45. Sincesubstantially three-fourths of the resistance section 45, is shunted,the degree of maximum illumination possible, under this setting is 7 5%.To obtain less illumination during the scene, the contact 55 is movedaway from the point/51 to a portion of the resistance ele- .1 nava Vment 38 in the control-winding circuit. It

will be seen from the foregoing, that the apparatus is flexible andcapable of producing I any desired predetermined lighting effects at anytime during a scene and that these effects may be predetermined bypresetting the adjustable contacts 53 with relation to their respectivesections. Byproviding a secondary or control reactor, theuni-directionalcurrent required for as the reactor 13, is relativelysmall and, consequently, the wires of the resistance element or unit 37may be made in such form that it requires very little space upon theswitchboard. a c r While I have illustrated but one embodiment of myinvention, it will be apparent to those skilled in the art that Variouschanges, modifications, substitutions, additions "and omissions may bemade in the apparatus illustrated without departing fromfthe spiritsandscope of my invention, asset forth in the appended claims,

I claim as my invention: 1. Circuit-controlling apparatus comprising auni-dircctional-current-supply circuit, a reactor having auni-directional-currentcontrol winding connected to the supply circuitand a resistance unit for'controlling the current supplied tothe controlwinding comprising a plurality of adjustable resistor sections connectedin parallel across the supply circuit, one of the conductors of whichcomprises a resistance element to which the sections are connected atspaced intervals and a movable contact connected in the circuit forengaging the resistance element at different points. i

"2. Circuit-controlling apparatus comprising auni-directional-current-supply circuit,

a reactor having a uni-directional-currentcontrol Winding connected tothe supply circuit and a resistance unit for controlling the currentsupplied to the control winding comcircuit, one of the conductors ofwhich comprises a resistance element to which the sections are connectedat spaced intervals and a movable contact connected in the circuit forengaging the resistance element at diflerent points, the resistance ofthe said element between any two resistor sections being greater thanthat of a resistor section.

'3. A presettable rheostat comprisinga plurality of adjustable resistorsections connected control-ling a reactor of large capacity, suchprising a plurality of adjustable resistor secf tions connected inparallel across the supply rent at difl'erentpoints long the saidelement.

5. In a current-controlling system, in combination, a source ofalternating current, a-

source of uni-directional current, a load circuit, a reactor forcontrolling the current supplied from the alternating-current source tothe loadcircuitand having a direct-current control winding, a secondreactor having an alternating-current winding connected to thealternating-current source and having a control winding, a rectifier forrectifying current from the alternating-current winding of the secondreactor and supplying corresponding uni-directional current to thecontrol Winding ofthe first reactor, and a resistance unit forcontrolling the direct current supplied to the control winding of thesecond reactor, said resistance unit comprising a plurality ofadjustable resistor sections connected in parallel across thedirect-current supply circuit,

one of the conductors of which comprises a a resistance element to whichthe sections are connected at spaced intervals and a movable contactconnected in the circuit for engaging the resistance element atdifferent points.

In testimony whereof, I have hereunto subscribed my name this. 8th dayof November,

' ROY J. WENSLEY.

in parallel between conductors of a current source; one of theconductors comprising a Jresistance element to which the sections areconnected at spaced intervals and a movable.

contact member for taking ofi' current at different points along thesaid element.

4. A presettable rheostat comprising-a plu- C5 rality of adjustableresistor sections each

